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Abstract Understanding the physiological concepts of oxygen delivery is essential to discern the mechanisms that influence its increase, reduction or maintenance in the body. This text explores the different mechanisms that help maintain oxygen delivery even in the face of reduced hemoglobin levels. Adequate oxygen delivery ensures tissue and metabolic balance, which is crucial to avoid harmful consequences such as metabolic acidosis and cellular dysoxia. The complex interaction between variables such as cardiac output, hemoglobin and heart rate (HR) plays a fundamental role in maintaining oxygen delivery, allowing the body to temporarily adjust to situations of anemia or high metabolic demand. It is important to emphasize that blood transfusions should not be based on fixed values, but rather on individual metabolic needs. Strategies to reduce myocardial consumption and monitor macro and micro hemodynamics help in making rational decisions. Individualizing treatment and considering factors such as blood viscosity in relation to the benefits of transfusion are increasingly relevant to optimize therapy and minimize risks, especially in complex clinical scenarios, such as neurocritical patients and trauma victims.
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Objective To study the correlation between ion concentrations of arterial and central venous blood in blood gas anal‐ysis .Methods This prospective study was performed in 72 patients with a central venous catheter and an artery catheter .A central venous blood sample and an artery blood sample were obtained at the same time after 10 minutes′anesthesia induction .Correlation analysis of the ion concentrations such as Na+ ,K+ ,Ca2+ between those in arterial and central venous blood were performed .The ion concentrations were determined by using GEM Premier 3000 Blood Gas Analysis System .Results The concentration value of Na+ in artery blood was (138 .81 ± 2 .40)mmol/L and in central venous blood was (139 .90 ± 2 .39)mmol/L ,there was significant difference between them(P0 .01) .The values of Ca2+ in artery blood was (1 .30 ± 0 .04)mmol/L and in central venous blood was (1 .32 ± 0 .05)mmol/L ,which were significantly different(P<0 .01) .Conclusion There is significant difference between Na+ ,Ca2+ concentrations in arterial blood gas analysis and those in central venous blood gas analysis ,central venous blood is relatively higher than artery blood ,while no statistically significant difference is observed for K+concentration .
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Bicarbonate (HCO3-) measurement in serum or plasma from a sample of venous blood is routinely practiced in hospital patient management. HCO3- status can also be assumed from Blood gas analysis requiring arterial blood as sample which is cumbersome for both patients and doctors. This study was undertaken to evaluate the extent of agreement among biocarbonate values obtained during venous, arterial blood gas analysis and conventionally measured serum bicarbonate levels in a group of intensive care unit (ICU) patients to determine whether conventionally measured serum HCO3- (from peripheral venous blood) and calculated HCO3-values (from arterial blood gas [ABG] analyzers) can be used interchangeably. A total of 51 adult patients with diverse medical conditions, presenting at a tertiary health centre ICU were enrolled in this study when deemed by the treating physician to have an ABG analysis. Arterial and venous samples were taken as close in time as possible for blood gas analysis and routine blood tests. Bland-Altman analyses were used to compare the three methods. The HCO3- levels from ABG, Venous Blood gas (VBG) and tconventionally measured serum HCO3- showed acceptably narrow 95% limits of agreement using the Bland-Altman method. VBG reveals higher level of agreement with the ABG bicarbonate values compared to measured serum HCO3-. Thus, venous blood can be an alternate for arterial blood where ABG analyzer is available. conventionaly serum HCO3- measurements can also be useful and used as substitute for an expensive ABG analyzer in resource constrained health care sectors when required.
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This investigation was undertaken to determine whether venous blood, sampled under carefully controlled conditions, was an acceptable alternative to arterial blood for the measurement of arterial blood gas analysis. The arterial values for Pco2, pH, base excess and oxygen saturation were compared with the values of blood samples drawn simultaneously from the cephalic, external jugular and internal jugular vein during inhalation general anesthesia with 50% oxygen concentration in 25 cases. The results were as follows: 1) The blood gas analysis values of cephalic venous blood were closely comparable to those of arterial blood. There was no significant difference between the Pci2, pH and base excess of cephalic venous and arterial blood. 2) Although the oxygen partial pressure in cephalic venous blood was significantly less than that in arterial blood, the difference in oxygen saturation was small. 3) The blood gas analysis values of external jugular venous blood were between the cephalic venous blood and the internal jugular venous blood values. Those show that venous blood was arterialized and in general anesthesia, it's Pco2, pH and oxygen saturation will be near endough to those of the arterial blood. Although the oxygen partial pressure in venous blood was significantly less than that in arterial blood, the difference in oxygen saturation was small. Therefore arterialized venous blood from the cephalic vein may provide a reasonable estimate of presence or absence of hypoxia. in this study, we feel that the use of cephalic venous blood for Pco2, pH and oxygen saturation determination during general anesthesia is a reliable indirect method of arterial blood sampling.